The present invention relates to adjustable supports for aircraft interior equipment, in particular, adjustable supports for aircraft seating and the like.
According to the General Aviation Crash Worthiness Project of the National Transportation Safety Board (“NTSB”), incidents of severe injuries and fatalities in survivable crashes of the general aviation fleet could be significantly improved by the use of energy absorbing seats and occupant restraints. According to one study conducted by the NTSB, many of the seats in the general aviation fleet broke or come off the seat tracks during survivable crashes. In one study, 44% of the occupied seats involved in general aviation crashes became detached from the airplane structure, usually because the seat feet or legs broke or separated. In one case the seat came loose, which allowed the occupant, who had survivable injuries, to fall out of the airplane and drown in shallow water. In another case, the seat frame collapsed allowing the rear legs to move closer to the front legs which allowed the rear of the seat to rotate down accelerating the occupant toward the floor.
In addition to failures caused by the seat structure itself, floor warping due to collapsing of the airframe can cause seats to fail. As the aircraft floor warps, extra stresses are placed on the seat feet as the seat resists changing its original shape to accommodate the floor warp. Floor warping can also be caused by excessive side loads imparted to the seat by deceleration other than along the longitudinal axis of the aircraft. For example, with a misalignment of only ten degrees, a 9-g forward acceleration can create a side load of 1.2 g on the seat feet.
Prior art aircraft seating has addressed the need for the seat to remain attached to the floor in spite of floor warping in a number of ways, including through the use of a flexible seat frame such the Piper Aircraft, Inc.'s “S-tube” seat. Another aircraft seat capable of accommodating floor warping includes a thin “fin” machined between the side structure of the seat and the track gripper. The fin flexes to accommodate the warping of the floor while maintaining the track gripper in contact with the seat track. What is needed, however, is an aircraft seat capable of accommodating floor warping during a crash that is also capable of moving along a non-linear seat track as is required in modern aircraft.